Aerial delivery is a term used to describe extracting an item from an aircraft in flight and then enabling a safe recovery of the item by use of an aerodynamic decelerator, which is most often a parachute system. Additionally, the aerial delivery operation is typically conducted from a cargo-type aircraft. The process may utilize very specific aerial delivery equipment and may adhere to very specific aerial delivery operational procedures. Often, the extracted item consists of an aerial delivery system containing cargo of some sort.
Two general types of extraction are utilized. Gravity extraction is the technique of using positive aircraft pitch angle, or by using some other force to cause the item to simply roll or slide out of the aircraft, which is typically followed by a parachute being deployed by a lanyard that is anchored to the aircraft. Parachute extraction is a technique whereby a parachute is first deployed out the rear of the cargo compartment, and the parachute is used to pull the item from the aircraft. Both techniques may conform to guidelines regarding length, weight, mass, etc., of the item being extracted in order to achieve a safe extraction operation. Generally speaking, relatively short and/or relatively lightweight items may be gravity extracted, but relatively long and/or relatively heavy items may preferably be parachute extracted, which removes the item from the aircraft quickly to prevent it from adversely affecting the aircraft's center of balance.
Items having a generally cylindrical shape, such as bombs that are powered by gravity, will typically be released from the belly or wing of a bomber or fighter aircraft. In practice, these items are released vertically but their longitudinal axis is substantially horizontal. Because the lower bomb racks in a bomb bay may be repositioned before other items can be released from racks above them, a simultaneous release of all items in the bomb bay cannot generally be conducted. The relatively long release time, coupled with a relatively high airspeed that is a feature of these aircraft, prevents the items from impacting in a concentrated area. Instead, the resulting impact path of the items is quite lengthy and the resulting impact effect is known as carpet bombing.
For aerial launching of chemical energy powered items, such as missiles, yet another technique is used. In this scenario, items are loaded into linear guidance devices, which are typically referred to as launchers. Typically, these launchers are either tubular or monorail (dovetail) in design, and are mounted substantially horizontally on fighter airplanes or helicopters. In practice, these items are generally powered by a self-contained rocket motor, allowing only one item to be loaded per launcher. Otherwise, the rocket blast from the front item could damage the item behind it, perhaps even causing it to explode while it is still in the launcher.
In yet another scenario, the GBU-43/B Massive Ordinance Air Blast (“MOAB”) munition is secured in a cradle atop an aerial delivery system that is parachute extracted from the cargo compartment of a cargo aircraft. The MOAB cradle is just that—a cradle; and, because the MOAB is a winged item, it must be separated from its cradle immediately outside the aircraft, with the extraction parachute still attached to the aerial delivery system, before the cradle can pitch or roll significantly—otherwise, the MOAB is likely to be damaged or released in an undesirable attitude. In the separation process, the MOAB has forward momentum due to inertia imparted by the aircraft, but the aerial delivery system and cradle will slow significantly, due to drag created by the still attached extraction parachute. The aerial delivery system will also pitch, with its leading edge going downward due to gravity and aerodynamic forces. The combination of relative longitudinal motion and a pitch-down of the aerial delivery system and cradle, allow the platform and cradle to move down and rearward, away from the MOAB. However, because this separation technique does not provide linear guidance control, or roll and yaw control, relative to the cradle, the rear control surfaces of the MOAB must be in a retracted configuration until after the separation event has occurred. Even though this marginally controlled separation technique is acceptable for the MOAB, it may be unsuitable if the separation event were significantly delayed after the system has been released from the aircraft. Further, because the separation technique provides no directional control or roll and yaw control for the separating item, it may be unsuitable for launching items with extended rear-mounted control surfaces, such as fins. With no directional or roll and yaw control, it may also be unsuitable for simultaneously launching multiple items that have any type of extended control surfaces.